Lighting system and method

Abstract

A lighting system and method ( 1 ) is disclosed having a pulse-width modulation (PWM) lighting system and method for use in environments where the PWM ratio is variable, for example though not exclusively, in 42V and/or dual-voltage electrical systems in automotive applications.

1. A lighting system for driving light bulbs having a lower voltage tolerance than the voltage supply to the system, comprising:
 a pulse width modulator converter supplied with a required voltage from a system source voltage supply of the system for regulating an average output signal of the pulse width modulator converter supplied to a register to selectively connect the output signal of the pulse width modulator converter to a light bulb selected by the converter supply from a plurality of light bulbs, each light bulb having a lower voltage tolerance than the system voltage, the register and converter synchronised via a clock source, wherein the converter drives a single light bulb at any one time even with a variable PWM mark-space ratio. 
 
   
   
     2. A lighting system as claimed in  claim 1 , wherein the system further comprises of a light bulb driver connected between each light bulb and register. 
   
   
     3. A lighting system as claimed in  claim 1 , wherein the pulse width modulator comprises of a comparator with one input receiving a required voltage, and another input receiving the output signal of the converter from a D-type flip-flop that receives the output signal of the comparator, feedback through a resistor and capacitor, for regulating the average output signal. 
   
   
     4. A lighting system as claimed in  claim 2 , wherein the pulse width modulator comprises of a comparator with one input receiving a required voltage, and another input receiving the output signal of the converter from a D-type flip-flop that receives the output signal of the comparator, feedback through a resistor and capacitor, for regulating the average output signal. 
   
   
     5. A lighting method for driving light bulbs having a lower voltage tolerance than the voltage supply to the system, comprising the steps of:
 supplying a requited voltage from system source voltage from a system source voltage supply; 
 regulating an average output signal from a pulse width modulator converter supplied with the system source voltage from the source system supply; 
 supplying the regulated average output signal to a register, the register and converter synchronised via a clock source; and 
 selectively connecting the output signal of the pulse width modulator converter from the register to a single light bulb at any one time from a plurality of light bulbs, even with a variable PWM mark-space ratio, wherein each light bulb having a lower voltage tolerance than the system voltage supply. 
 
   
   
     6. A lighting method as claimed in  claim 5 , wherein the step of selectively connecting the output signal of the pulse width modulator converter from the register to a single light bulb further comprises a light bulb driver connected between each light bulb and register. 
   
   
     7. A lighting method as claimed in  claim 5  wherein the step of regulating an avenge output signal from the pulse width modulator converter further comprises comparing at a comparator in the pulse width modulator converter one input receiving the required voltage, with another input receiving the output signal from a D-type flip-flop that receives the output signal of the comparator, feedback through a resistor and capacitor, for regulating the average output signal. 
   
   
     8. A lighting method as claimed in  claim 6  wherein the step of regulating an average output signal from the pulse width modulator converter further comprises comparing at a comparator in the pulse width modulator converter one input receiving the required voltage, with another input receiving the output signal from a D-type flip-flop that receives the output signal of the comparator, feedback through a resistor and capacitor, for regulating the average output signal.